Optical packet switching system

Abstract

An optical packet switching system includes a plurality of network elements for transmitting and receiving optical packet signals. Each network element includes an optical signal-to-noise ratio (OSNR) acquiring unit for acquiring the OSNR of each optical packet signal, an average value calculating unit for calculating the average value of the OSNRs of optical packet signals received within a predetermined time duration for each of the plurality of source network elements, and a difference information transmitter for calculating the difference between the calculated average value of the OSNRs and a target value of the OSNRs and then transmitting the difference to a network element corresponding to the difference. A source network element that has received the difference information adjusts the characteristics of an optical packet signal to be transmitted in a manner such that the difference is reduced.

What is claimed is: 
     
       1. An optical packet switching system including a plurality of transmitting network elements for transmitting optical packet signals and a receiving network element for receiving the optical packet signals transmitted from the transmitting network elements, the receiving network element comprising:
 an optical signal-to-noise ratio (OSNR) acquiring unit configured to acquire an OSNR of each of the optical packet signals received; 
 an average value calculating unit configured to calculate an average value of the OSNRs of optical packet signals received within a predetermined time duration for each of the plurality of transmitting network elements that are sources of the optical packet signals; and 
 a difference information transmitter configured to calculate, for each of the plurality of transmitting network elements, a difference between the calculated average value thereof and an average value of the ONSRs of all of the optical packet signals received within the predetermined time duration, and configured to transmit the difference to a transmitting network element associated with the difference, 
 wherein each of the transmitting network elements adjusts a characteristic of an optical packet signal to be transmitted in a manner such that the difference is reduced. 
 
     
     
       2. The optical packet switching system according to  claim 1 , wherein each of the transmitting network elements adjusts the light power and/or extinction ratio of the optical packet signal. 
     
     
       3. The optical packet switching system according to  claim 1 , wherein each of the transmitting network elements includes an optical amplifier device for amplifying the optical packet signal, estimating the ONSR of the optical packet signal, and appending information on the estimated OSNR to the optical packet signal. 
     
     
       4. The optical packet switching system according to  claim 3 , wherein the optical amplifier device estimates the OSNR of the optical packet signal to be outputted, based on the light power of the inputted optical packet signal and a noise figure of the optical amplifier device. 
     
     
       5. The optical packet switching system according to  claim 3 , wherein the optical amplifier device converts the estimated OSNR information into an optical signal and inserts the optical signal before or after the optical packet signal. 
     
     
       6. The optical packet switching system according to  claim 1 , wherein each of the transmitting network elements conveys information on the OSNR to the receiving network element using an optical supervisory channel.